US20070039105A1

US20070039105A1 - Apparatus for sensing vibration of washing machine and method thereof

Info

Publication number: US20070039105A1
Application number: US11/465,557
Authority: US
Inventors: Dong-Soo Lee; Dong-won Kim
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2005-08-19
Filing date: 2006-08-18
Publication date: 2007-02-22
Also published as: KR100788974B1; KR20070021787A

Abstract

An apparatus for sensing vibration of a washing machine capable of precisely detecting a vibration amount of a tub at each rpm bandwidth by dividing an rpm of a motor into a plurality of bandwidths and by using a multi-axis inertia sensor, and a method thereof. The method comprises: detecting an rpm of a motor; dividing the detected rpm into a plurality of bandwidths; and detecting a vibration amount of a tub at the divided bandwidths.

Description

RELATED APPLICATION

The present disclosure relates to subject matter contained in priority Korean Application No. 10-2005-0076412, filed on Aug. 19, 2005, which is herein expressly incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to an apparatus for sensing vibration of a washing machine and a method thereof, and more particularly, to an apparatus for sensing vibration of a washing machine capable of sensing vibration of a washing machine by dividing an rpm of a motor into a plurality of bandwidths.
2. Description of the Background Art
Generally, a washing machine serves to wash laundry by applying a mechanical force such as friction, vibration, etc. to the laundry immersed in washing water.
The washing machine performs a washing operation for washing laundry mixed with washing water by applying a mechanical force, a rinsing operation for separating the washing water from the laundry, and a dehydrating operation for separating the rinsing water from the laundry.
Hereinafter, a structure and an operation of the related art drum-type washing machine will be explained with reference to FIG. 1.
FIG. 1 is a construction view showing a drum-type washing machine in accordance with the related art. As shown, the washing machine comprises: a housing 11 having an inner space; an outer water tank 13 installed in the housing; a suspension unit 12 for supporting the outer water tank by connecting the housing 11 to the outer water tank 13 in the housing 11; a drum-type inner drum 14 installed in the outer water tank 131 for washing laundry; a driving unit 15 for rotating the inner drum 14; a rotation shaft 16 for transmitting a driving force of the driving unit 15; and an outer door 17 attached to a front surface of the housing 11.
In the drum-type washing machine, water is supplied to the inner drum 14 at the time of a washing operation and a rinsing operation. When water is filled by a certain level, the supply is stopped and the inner drum 14 is repeatedly rotated in a forward direction and a backward direction by the driving unit 15.
At the time of a dehydrating operation, the water inside the inner drum 14 is drained, and the inner drum 14 is rotated with a low speed in a forward direction and a backward direction by the driving unit 15 thereby to perform a laundry uniformly-distributing process. Then, the inner drum 14 is accelerated thus to perform a dehydrating operation.
When an unbalance of the laundry is caused in the washing machine, noise and vibration are generated at the time of the dehydrating operation.
In order to solve the problem, in the dehydrating operation, a vibration amount is detected according to an rpm of the motor. When the detected vibration amount is less than a reference value, a dehydrating operation of a subsequent step is performed. However, when the detected vibration amount is more than the reference value, a laundry uniformly-distributing process is performed and then a dehydrating operation of a subsequent step is performed.
In order to detect a vibration amount of the washing machine, an inertia sensor such as a vibration sensor or an acceleration sensor is used. The inertia sensor momentarily detects a physical force such as acceleration, vibration, impact, etc. thus to output it as an electrical signal.
However, the related art has the following problem. Since a sensor having the same sensitivity at an entire range of the rpm of the motor is used to detect each vibration amount, a vibration amount is not precisely detected in a certain range of the rpm due to noise.
More concretely, a general inertia sensor has an rpm bandwidth to detect a vibration amount with an optimum sensitivity, and the rest rpm bandwidths having an inferior sensitivity due to noise. However, since the related art inertia sensor does not consider a sensitivity for an rpm of a motor, a vibration amount may detected with an inferior sensitivity in a certain range of the rpm.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide an apparatus for sensing vibration of a washing machine capable of precisely detecting a vibration amount at each rpm bandwidth of a motor by dividing an rpm of the motor into a plurality of bandwidths and by using a plurality of inertia sensors or one multi-axis inertia sensor, and a method thereof.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a method for sensing vibration of a washing machine, comprising: detecting an rpm of a motor; dividing the detected rpm into a plurality of bandwidths; and detecting a vibration amount of a tub at the divided bandwidths.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided an apparatus for sensing vibration of a washing machine, comprising: an rpm detecting unit for detecting an rpm of a motor; an rpm bandwidth dividing unit for dividing the detected rpm into a plurality of bandwidths; and a vibration amount detecting unit for detecting a vibration amount of a tub at the divided bandwidths.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:
FIG. 1 is a view showing a structure of a drum-type washing machine in accordance with the related art;
FIG. 2 is a graph showing an rpm of a motor of a washing machine;
FIG. 3 is a graph showing a sensitivity of each axis sensor according to each rpm bandwidth of a multi-axis inertia sensor;
FIG. 4 is a flowchart showing a method for sensing vibration of a washing machine according to the present invention; and
FIG. 5 is a flowchart showing an apparatus for sensing vibration of a washing machine according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Hereinafter, with reference to FIGS. 2 to 5, will be explained an apparatus for sensing vibration of a washing machine capable of precisely detecting a vibration amount at each rpm bandwidth of a motor by dividing an rpm of a motor into a plurality of bandwidths and by using a plurality of inertia sensors or one multi-axis inertia sensor, and a method thereof.
According to one embodiment of the present invention, the a plurality of bandwidths include an unbalance detecting bandwidth of a low speed, a resonance detecting bandwidth of a middle speed, and a maximum speed determining bandwidth of a high speed. According to another embodiment of the present invention, a vibration amount of a tub of a washing machine is detected with using one multi-axis inertia sensor consisting of a plurality of axis sensors having a maximum vibration-detection sensitivity at each rpm bandwidth.
A method for sensing vibration of a washing machine according to one embodiment of the present invention comprises detecting an rpm of a motor; and detecting a vibration amount of a tub based on the detected rpm.
The step of detecting an rpm of a motor comprises detecting an output current of the motor; comparing the detected output current with a reference current corresponding to a preset rpm; and detecting an rpm of the motor based on the comparison result.
The step of detecting an rpm of a motor comprises detecting an input voltage and an output current of the motor; comparing the detected voltage and current with a reference voltage and a reference current each corresponding to a preset rpm; and detecting an rpm of the motor based on the comparison result.
The step of detecting a vibration amount of a tub comprises detecting a vibration amount of the tub in one axis direction and in a multi-axis direction.
The step of detecting a vibration amount of a tub comprises detecting a maximum vibration-detection sensitivity according to the detected rpm with using one multi-axis inertia sensor consisting of a plurality of axis sensors.
According to another embodiment of the present invention, a method for sensing vibration of a washing machine comprises: detecting an rpm of a motor; dividing the detected rpm into a plurality of bandwidths; and detecting a vibration amount of a tub at the divided bandwidths.
The step of detecting an rpm of a motor comprises detecting an output current of the motor; comparing the detected output current with a reference current corresponding to a preset rpm; and detecting an rpm of the motor based on the comparison result.
The step of detecting an rpm of a motor comprises detecting an input voltage and an output current of the motor; comparing the detected voltage and current with a reference voltage and a reference current each corresponding to a preset rpm, and detecting an rpm of the motor based on the comparison result.
The step of dividing the detected rpm into a plurality of bandwidths comprises setting a low speed bandwidth as an unbalance detecting bandwidth; setting a middle speed bandwidth as a resonance detecting bandwidth; and setting a high speed bandwidth as a maximum speed determining bandwidth.
The step of detecting a vibration amount of a tub comprises detecting a vibration amount of the tub in one axis direction and in a multi-axis direction.
The step of detecting a vibration amount of a tub comprises detecting a maximum vibration-detection sensitivity at the divided bandwidths with using one multi-axis inertia sensor consisting of a plurality of axis sensors.
FIG. 2 is a graph showing an rpm of a motor according to time. As shown, the rpm of the motor is divided into a first bandwidth (maximum rpm=V1) denoting an rpm according to time of 0˜t1, a second bandwidth (maximum rpm=V2) denoting an rpm according to time of t1˜t2, and a third bandwidth (maximum rpm=V3) denoting an rpm according to time after t2. Since vibration is mainly caused due to unbalance in the first bandwidth, the first bandwidth of a low speed is designated as an unbalance detecting bandwidth. Since vibration is mainly caused due to resonance in the second bandwidth, the second bandwidth of a is middle speed is designated as a resonance detecting bandwidth. And, since vibration is mainly caused due to a maximum speed in the third bandwidth, the third bandwidth of a high speed is designated as a maximum speed determining bandwidth.
In order to detect each vibration amount of the first to third bandwidths, a first inertia sensor having a maximum vibration-detection sensitivity (a maximum sensitivity for detecting vibration) at the maximum rpm (V1) of the first bandwidth, a second inertia sensor having a maximum vibration-detection sensitivity at the maximum rpm (V2) of the second bandwidth, and a third inertia sensor having a maximum vibration-detection sensitivity at the maximum rpm (V3) of the third bandwidth are used.
That is, each inertia sensor having a maximum bandwidth passing characteristic at each rpm of V1, V2, and V3 is used to precisely detect a vibration amount of each rpm bandwidth.
Preferably, a multi-axis inertia sensor consisting of three axis sensors each having a maximum vibration-detection sensitivity at the three rpm bandwidths is used. That is, a vibration amount is precisely detected at each rpm bandwidth with using one multi-axis inertia sensor that an X-axis sensor, a Y-axis sensor, and a Z-axis sensor are designed to react to each vibration generated at each rpm of V1, V2, and V3 the most sensitively.
The multi-axis inertia sensor indicates one inertia sensor for detecting an acceleration, an inertia variation, impact, etc. at a plurality of axes.
FIG. 3 is a graph showing a sensitivity of each axis sensor according to each rpm bandwidth of a multi-axis inertia sensor. The multi-axis inertia sensor consists of an X-axis sensor, a Y-axis sensor, and a Z-axis sensor. The X-axis sensor has a maximum vibration-detection sensitivity at the rpm of V1, the Y-axis sensor has a maximum vibration-detection sensitivity at the rpm of V2, and the Z-axis sensor has a maximum vibration-detection sensitivity at the rpm of V3.
FIG. 4 is a flowchart showing a method for sensing vibration of a washing machine according to the present invention. As shown, a method for sensing vibration of a washing machine comprises dividing an rpm of a motor into first to third bandwidths (S31); detecting a first vibration amount with using a first inertia sensor having a maximum vibration-detection sensitivity at a first bandwidth (S32A); comparing the first vibration amount with a first reference value (S33A); and when the first vibration amount is more than the first reference value, performing a laundry uniformly-distributing process (S34A).
The method for sensing vibration of a washing machine comprises: when the first vibration amount is less than the first reference value, accelerating the rpm into the second bandwidth, and then detecting a second vibration amount with using a second inertia sensor having a maximum vibration-detection sensitivity at the second bandwidth (S32B); comparing the second vibration amount with a second reference value (S33B), and when the second vibration amount is more than the second reference value, performing a laundry uniformly-distributing process (S34B).
The method for sensing vibration of a washing machine comprises: when the second vibration amount is less than the second reference value, accelerating the rpm into the third bandwidth, and then detecting a third vibration amount with using a third inertia sensor having a maximum vibration-detection sensitivity at the third bandwidth (S32C); comparing the third vibration amount with a third reference value (S33C); and performing a laundry uniformly-distributing process (S34C) when the third vibration amount is more than the third reference value, and performing a dehydrating operation when the third vibration amount is less than the third reference value.
As aforementioned, the X-axis sensor, the Y-axis sensor, and the Z-axis sensor of the multi-axis inertia sensor are used to detect each vibration amount at the first to third rpm bandwidths.
An apparatus for sensing vibration of a washing machine according to the present invention, comprises: an rpm detecting unit 52 for detecting an rpm of a motor 51; an rpm bandwidth dividing unit 53 for dividing the detected rpm into a plurality of bandwidths; and a vibration amount detecting unit 54 for detecting a vibration amount of a tub at the divided bandwidths.
The rpm detecting unit 52 includes an encoder for calculating the number of rotations of a rotor of the motor so as to detect the rpm of the motor.
The rpm detecting unit 52 includes a hole sensor for detecting a current in a rotation direction of the motor so as to detect the rpm of the motor.
The rpm detecting unit 52 includes a plurality of vibration amount sensors for detecting each vibration amount of the tub in one axis direction and in a multi-axis direction.
The vibration amount detecting unit 53 includes one multi-axis inertia sensor consisting of a plurality of axis sensors having each maximum vibration-detection sensitivity at each rpm bandwidth.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims

1. A method for sensing vibration of a washing machine, comprising:

detecting an rpm of a motor;

detecting a vibration amount of a tub based on the detected rpm.

2. The method of claim 1, wherein the step of detecting an rpm of a motor comprises:

detecting an output current of the motor;

comparing the detected output current with a reference current corresponding to a preset rpm; and

detecting an rpm of the motor based on the comparison result.

3. The method of claim 1, wherein the step of detecting an rpm of a motor comprises:

detecting an input voltage and an output current of the motor;

comparing the detected voltage and current with a reference voltage and a reference current each corresponding to a preset rpm; and

detecting an rpm of the motor based on the comparison result.

4. The method of claim 1, wherein the step of detecting a vibration amount of a tub comprises detecting a vibration amount of the tub in one axis direction and in a multi-axis direction.

5. The method of claim 1, wherein the step of detecting a vibration amount of a tub comprises detecting a maximum vibration-detection sensitivity according to the detected rpm with using one multi-axis inertia sensor consisting of a plurality of axis sensors.

6. A method for sensing vibration of a washing machine, comprising:

detecting an rpm of a motor;

dividing the detected rpm into a plurality of bandwidths; and

detecting a vibration amount of a tub at the divided bandwidths.

7. The method of claim 6, wherein the step of detecting an rpm of a motor comprises:

detecting an output current of the motor;

detecting an rpm of the motor based on the comparison result.

8. The method of claim 6, wherein the step of detecting an rpm of a motor comprises:

detecting an input voltage and an output current of the motor;

detecting an rpm of the motor based on the comparison result.

9. The method of claim 6, wherein the step of dividing the detected rpm into a plurality of bandwidths comprises:

setting a low speed bandwidth as an unbalance detecting bandwidth,

setting a middle speed bandwidth as a resonance detecting bandwidth; and

setting a high speed bandwidth as a maximum speed determining bandwidth.

10. The method of claim 6, wherein the step of detecting a vibration amount of a tub comprises detecting a vibration amount of the tub in one axis direction and in a multi-axis direction.

11. The method of claim 6, wherein the step of detecting a vibration amount of a tub comprises detecting a maximum vibration-detection sensitivity at the divided rpm bandwidths with using one multi-axis inertia sensor consisting of a plurality of axis sensors.

12. An apparatus for sensing vibration of a washing machine, comprising:

an rpm detecting unit for detecting an rpm of a motor;

an rpm bandwidth dividing unit for dividing the detected rpm into a plurality of bandwidths; and

a vibration amount detecting unit for detecting a vibration amount of a tub at the divided bandwidths.

13. The apparatus of claim 12, wherein the rpm detecting unit comprises an encoder for calculating the number of rotations of a rotor of the motor so as to detect the rpm of the motor.

14. The apparatus of claim 12, wherein the rpm detecting unit comprises a hole sensor for detecting a current in a rotation direction of the motor so as to detect the rpm of the motor.

15. The apparatus of claim 12, wherein the rpm detecting unit comprises a plurality of vibration amount sensors for detecting each vibration amount of the tub in one axis direction and in a multi-axis direction.

16. The apparatus of claim 12, wherein the vibration amount detecting unit comprises one multi-axis inertia sensor consisting of a plurality of axis sensors having each maximum vibration-detection sensitivity at each rpm bandwidth.